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REVIEW 3 major objections 6 minor 7 cited by

Long-lived Axion-Like Particles from Tau Decays

T0 review · 3 major / 6 minor · reviewed 2026-08-06 · deepseek-v4-flash

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Pith's one-line read Tau decays are shown to be a copious source of long-lived leptophilic ALPs, with CHARM and BEBC data constraining the ALP decay constant up to $O(10^8)$ GeV in flavor-violating channels and SHiP projected to exceed those bounds by an…

desk verdict Tau-decay production of leptophilic ALPs is a real new channel, and the CHARM/BEBC constraints are plausible; the main caveat is the factor-of-several tau yield uncertainty, which the paper itself documents. read the letter →

arxiv 2507.15271 v1 pith:D5I2D52Z submitted 2025-07-21 hep-ph hep-ex

Yohei Ema , Patrick J. Fox , Matheus Hostert , Tony Menzo , Maxim Pospelov , Anupam Ray , Jure Zupan This is my paper
classification hep-phhep-ex
keywords axion-likeparticlesleptophilicALPstaudecaysbeamdumpexperimentsleptonflavorviolationlong-liveddisplacedvertexsearchesSHiP
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper is about axion-like particles (ALPs) that couple only to leptons and are light enough to be produced in tau decays, with masses between twice the electron mass and $m_\tau - m_e$. The central claim is that these particles are produced copiously—either through lepton-flavor-violating decays $\tau \to \ell a$ or through tau bremsstrahlung $\tau \to X \nu a$—and that because their derivative couplings suppress decays into lepton pairs, they are long-lived and can travel to distant detectors. Reinterpreting the old CHARM and BEBC beam-dump experiments as searches for displaced ALP decays places new constraints on the ALP decay constant $f_a$, reaching about $10^8$ GeV when flavor is violated and about $10^2$ GeV when it is conserved. The paper also projects that the planned SHiP experiment will be sensitive to $f_a$ values more than an order of magnitude beyond these existing bounds, making tau decays a competitive new production channel for feebly interacting particles.

What carries the argument

The central object is the dimension-five effective Lagrangian $\mathcal{L}_{\rm int} = (\partial_\mu a / 2 f_a) \sum_{i,j} g_{ij} (\bar{L}_i \gamma^\mu P_L L_j + \bar{\ell}_i \gamma^\mu P_R \ell_j)$, with the leptophilic ALP $a$ derivatively coupled to lepton currents at scale $f_a$. This derivative structure is what makes the ALP long-lived: the partial widths to $e^+e^-$ and $\mu^+\mu^-$ are proportional to the lepton masses squared, so the decays are suppressed and the particle can reach a distant detector. The production machinery is tau decay: flavor-violating two-body decays $\tau \to \ell a$ carry one power of Standard Model weak coupling and one power of $1/f_a$, while flavor-conserving channels are tree-level bremsstrahlung off tau decays with an additional $G_F$ suppression. The analysis then converts past and future detector geometries into a decay-in-flight probability $P_{\rm decay} = B(a \to \ell_1 \ell_2) \exp(-\Gamma_a L / \gamma_a \beta_a) (1 - \exp(-\Gamma_a \lambda / \gamma_a \beta_a))$, which is what turns old beam-dump data into new limits.

What would settle it

Measure the inclusive $D_s \to \tau \nu_\tau$ production rate and spectrum at 120 GeV and 400 GeV proton beams (for example with the DsTau/NA65 emulsion detector or with charm-tagged data at SHiP) and compare with the Pythia 8 SoftQCD prediction used here; a discrepancy larger than roughly a factor of two in the normalized yield would rescale the $f_a$ reaches and could strengthen or erase the CHARM and BEBC exclusions.

Watch

Extended reading notes

Core claim

On the paper's own terms, the discovery is that tau decays are an overlooked and efficient source of long-lived leptophilic ALPs. For anarchic flavor structure, the flavor-violating decay $\tau \to \ell a$ is enhanced relative to Standard Model tau decays by $(m_W^2/(m_\tau f_a))^2$, so even with $f_a$ as large as $10^8$ GeV the branching ratio is large enough to produce observable displaced decays. For flavor-conserving couplings, ALP bremsstrahlung in $\tau \to \pi \nu a$, $\tau \to \rho \nu a$, and $\tau \to \ell \nu \nu a$ is weaker but still yields new constraints around $f_a \sim 10^2$ GeV, and the ALP is long-lived below the dimuon threshold (or above it if the muon coupling is suppressed). The paper derives these rates analytically, simulates tau production at the NuMI, SPS, and LHC beams with Pythia 8, and finds that CHARM and BEBC data already exclude new parameter space while SHiP—and to a lesser extent FASER-2 and the Fermilab near detectors—will extend the reach.

Load-bearing premise

Everything rests on the simulated tau production rate at each beam: the number of $D_s$ mesons that decay into taus comes from Pythia 8, and if that rate is off by a factor of a few—as the paper's own comparison with a simplified charm-production model suggests—the quoted $f_a$ limits move by the same factor.

Editorial extensions

If this is right

  • CHARM and BEBC now constrain lepton-flavor-violating leptophilic ALPs with decay constants up to $f_a \sim 10^8$ GeV in the mass range $2 m_e < m_a < m_\tau - m_e$.
  • Lepton-flavor-conserving ALPs produced by tau bremsstrahlung are constrained at $f_a \sim 10^2$ GeV, complementing electron beam-dump and meson-decay limits.
  • SHiP, with $6 \times 10^{20}$ protons on target, is projected to probe $f_a$ values over an order of magnitude beyond existing constraints, and FASER-2 plus the NuMI near detectors extend coverage in specific lifetime regimes.
  • If the muon coupling is suppressed (muon-phobic or tau-philic flavor patterns), ALPs stay long-lived above the dimuon threshold, opening parameter space where only $e^+e^-$ and $\gamma\gamma$ decays are available.
  • The sensitivity is controlled by the inclusive tau yield, so any experiment that improves knowledge of $D_s \to \tau$ production directly sharpens these ALP limits.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The same recasting recipe applies to any long-lived particle produced in tau decays—heavy neutral leptons, dark scalars, and similar states—because the simulated tau yield is the shared ingredient.
  • Because the limits scale linearly with the tau yield, the factor-of-a-few spread between the Pythia simulation and the simplified $D_s$ production model shown in Appendix A implies a comparable systematic uncertainty on the absolute $f_a$ bounds.
  • Direct measurements of charm and $\nu_\tau$ production at the SPS (for example with emulsion or charm-tagging detectors) would test the production model and could convert the projected event-rate sensitivities into firm exclusions.
  • The same derivative-coupling mechanism suggests that heavier leptophilic ALPs, above the tau mass, could be probed through $W \to \tau (a \to \ell^+\ell^-) \nu$ at the LHC, a channel the paper notes but does not analyze.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 6 minor

Summary. The paper studies long-lived axion-like particles (ALPs) that couple exclusively to leptons, in the mass range between 2 m_e and m_tau - m_e. For lepton-flavor-violating (LFV) couplings, ALPs are produced in two-body tau decays tau -> l a; for lepton-flavor-conserving (LFC) couplings, they are produced via tau -> pi nu a, rho nu a, and l nu_l nu_tau a bremsstrahlung. The authors compute the relevant decay rates, including an analytic four-body phase-space integration for tau -> l nu_l nu_tau a, and evaluate tau yields at the NuMI, SPS, and LHC using Pythia 8. They reinterpret CHARM and BEBC beam-dump data to derive constraints on the ALP decay constant f_a, reaching O(10^8) GeV in LFV channels and O(10^2) GeV in LFC channels, and provide projections for SHiP, FASER(2), DUNE, microBooNE, ICARUS, NOvA, and protoDUNE, with SHiP expected to extend the sensitivity by over an order of magnitude beyond current limits.

Significance. If the results hold, the paper identifies tau decays as a key production channel for leptophilic ALPs and, through a reinterpretation of past CHARM and BEBC data, opens a new window on f_a up to O(10^8) GeV in LFV scenarios. The analytic decay formulas are presented in enough detail to be checked, and the publicly available code and the cross-check with SensCalc add to the paper's reliability. The projections for SHiP and FASER2 are concrete and falsifiable. The main limitations are the reliance on Pythia 8 SoftQCD for the absolute tau yield, the uncertainty of which is acknowledged but not propagated into the headline limits, and the simplified recast of the CHARM/BEBC detectors without efficiency modeling. These issues affect the precision of the headline numbers but the core calculation is internally consistent, so the paper merits revision rather than rejection.

major comments (3)
  1. [III A, Appendix A] The tau yield from Pythia 8 with SoftQCD only is the primary input for the ALP flux, and the paper's own Appendix A (Fig. 11) shows that an alternative D_s parameterization from Ref. [44] shifts the projected limits by a factor of a few in sqrt(m_a)/f_a. Section III A also notes that nu_tau flux estimates at SHiP vary by as much as an order of magnitude. These uncertainties are not displayed in the main figures, and the abstract and conclusions quote O(10^8) GeV and "over an order of magnitude" without a caveat. I ask the authors to include an uncertainty band in the main results, or at least to state explicitly in the abstract and conclusions that the quoted f_a values are subject to a factor-of-a-few systematic uncertainty from tau production.
  2. [III B, Table I] The CHARM and BEBC exclusions in Figs. 6-9 are obtained by requiring 2.3 signal events with zero background, using only geometric acceptance and simple energy cuts, and the text states that no detector efficiencies are applied. The cited experimental searches have finite efficiencies and analysis cuts, so this recast is an idealized event-rate sensitivity rather than a true exclusion. The authors should either fold in the actual efficiencies of the CHARM and BEBC detectors (which may be available from the original analyses) or consistently label the "bounds" as sensitivities throughout the text, abstract, and conclusions.
  3. [III A, Pythia setup] The description of the Pythia 8 setup is ambiguous: the text says that HardQCD is turned off and SoftQCD:all is used to simulate D_s, psi(2S), and direct tau production. In standard Pythia 8, open-charm production is driven by hard 2-to-2 QCD processes, so it is not obvious how charm is generated with HardQCD switched off. Please clarify how charm hadroproduction is enabled in your simulation and whether the resulting tau yields were validated against fixed-target charm production data or the nu_tau flux estimates in Refs. [36-39]. If the yields are only from SoftQCD remnants or a non-default charm-production switch, this should be stated precisely.
minor comments (6)
  1. [V, Conclusions] Typo: "scenarions" should be "scenarios" in the sentence "for flavor-violating ALP scenarions".
  2. [Fig. 4] The right panel label "FASER (Ep = 6.80 TeV)" is inconsistent with the text, which quotes sqrt(s) = 13.6 TeV for the LHC; use "E_p = 6.8 TeV" or "sqrt(s) = 13.6 TeV" for clarity.
  3. [Appendix B, Table II] The gamma-distribution parameters in Table II are listed as m_i, mu_i, lambda_i, but the text defines Gamma(x, alpha, lambda) with shape alpha and scale lambda. The mapping from the table columns to alpha and lambda is not explained.
  4. [III D] The sentence "tuning their overall effect epsilon, we find some agreement with Bertuzzo et al when epsilon ~ 0.5" is awkwardly phrased; rephrase for readability.
  5. [Fig. 10 caption] Typo: "Pyhia8" should be "Pythia 8".
  6. [II, first paragraph] The notation "Br(D±s -> tau ±(-) nu_tau)" is confusing; write "Br(D_s± -> tau± nu_tau)" (and similarly for D± decays).

Circularity Check

0 steps flagged · score 0.0 of 10

Self-contained EFT-to-beam-dump calculation; only ancillary self-citations, no load-bearing circularity.

full rationale

The derivation chain is self-contained. Production rates follow from the derivative lepton-current Lagrangian (I.5), with analytic expressions for tau -> l a (II.1), tau -> pi nu a (II.5), tau -> rho nu a (II.9), and tau -> l nu nu a (II.12), and for ALP decays (II.16)-(II.18). The CHARM/BEBC limits are obtained by folding these rates with tau yields from Pythia 8 (Sec. III A), detector geometry (III.1), and the published null results, with no parameter fitted to the constrained observable. The tau-yield input is externally based, and the paper explicitly quantifies its uncertainty in Sec. III A and Appendix A against Ref. [44]; this is an input-robustness caveat, not circularity. Self-citations (e.g., Ref. [13] for SN cooling curves and the isotropy statement, Ref. [121] in context) are ancillary comparisons and are not load-bearing for the central constraints; the central calculation does not reduce to a self-citation chain. No fitted parameter is renamed as a prediction, and no known result is merely relabeled.

Assumptions & free parameters 3 free parameters · 5 assumptions · 1 invented entities

The main assumptions are the standard EFT and simulation choices. The benchmark coupling patterns are hand-chosen, and the Pythia tau yield is the largest source of systematic uncertainty. The only invented entity is the ALP itself. The circularity burden is low because constraints are derived from experimental data and the model only defines the signal.

free parameters (3)
  • benchmark coupling patterns g_ij = 0, 1, or lambda in {5e-2, 1e-2, 5e-3, 1e-3}
    The paper explores representative flavor patterns (anarchy, hierarchy, universal LFC, mu-phobic, tau-philic). These are hand-chosen benchmarks that define the scenarios, not fit to data. They are not free parameters in the sense of being adjusted to make the claim true, but the choice of benchmarks affects all conclusions.
  • tau production fits (Table II) = nuisance values for gamma and xF exponential parameters
    Analytic fits to Pythia output used to speed up simulation. The paper states the main results use direct Pythia events, not these fits, so they are not load-bearing for the constraints.
  • Pythia 8 Monash tune settings = default Monash 2013 tune, SoftQCD:all, HardQCD off
    MC generation settings for charm production are not fit to data in this paper, but the paper notes a possible order-one systematic in tau yields. This is an uncertainty source, not a fitted free parameter.
assumptions (5)
  • domain assumption Effective field theory with derivative couplings to leptons only, as in Eq. (I.5), captures the relevant new physics
    The defining assumption of the scenario, stated in the introduction and Eq. (I.5). All results depend on this EFT choice.
  • domain assumption The tau decay width is dominated by SM channels and the ALP production is a small perturbation
    The paper uses SM tau widths to compute branching ratios and the tau lifetime constraint in Section IV C. This is the standard EFT assumption.
  • domain assumption Pythia 8 with SoftQCD:all and Monash tune provides a reliable model for D_s and tau production at NuMI, SPS, and LHC
    The tau yields are obtained from Pythia 8. The paper checks this against a simplified parameterization in Appendix A and finds factor-of-few disagreements. This is an acknowledged assumption with quantified uncertainty.
  • domain assumption The CHARM and BEBC experimental acceptances and zero-background assumption are correctly modeled
    The paper uses the detector parameters in Table I and assumes zero background for deriving 90% CL exclusions from CHARM and BEBC. This is stated in Section III C.
  • domain assumption Standard model backgrounds are negligible or can be rejected with the assumed cuts
    For future experiments, only event-rate sensitivities are computed; backgrounds and efficiencies are not modeled. For CHARM and BEBC, the paper relies on the original analyses' background suppression.
invented entities (1)
  • ALP field a with derivative couplings to leptons (g_ij/fa)
    purpose: New light particle whose production in tau decays and decay to lepton pairs is used to derive constraints and sensitivities
    The ALP is a hypothesized particle not yet observed. The paper provides no direct experimental evidence for its existence, only constraints assuming it. It does make falsifiable predictions for future searches, but those are the object of the search, not independent evidence.

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Cite this review

Pith. "Pith review of Long-lived Axion-Like Particles from Tau Decays." pith.science (2026). https://pith.science/paper/D5I2D52Z

@misc{pith2026250715271,
  author       = {Pith},
  title        = {Pith review of: Long-lived Axion-Like Particles from Tau Decays},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/D5I2D52Z}},
  note         = {Machine review of arXiv:2507.15271}
}
abstract

Axion-like particles (ALPs) are well-motivated examples of light, weakly coupled particles in theories beyond the Standard Model. In this work, we study long-lived ALPs coupled exclusively to leptons in the mass range between $2 m_e$ and $m_\tau - m_e$. For anarchic flavor structure the leptophilic ALP production in tau decays or from ALP-tau bremsstrahlung is enhanced thanks to derivative couplings of the ALP and can surpass production from electron and muon channels, especially for ALPs heavier than $m_\mu$. Using past data from high-energy fixed-target experiments such as CHARM and BEBC we place new constraints on the ALP decay constant $f_a$, reaching scales as high as $\mathcal{O}(10^8)$~GeV in lepton-flavor-violating channels and $f_a \sim \mathcal{O}(10^2)$~GeV in lepton-flavor-conserving ones. We also present projections for the event-rate sensitivity of current and future detectors to ALPs produced at the Fermilab Main Injector, the CERN SPS, and in the forward direction of the LHC. We show that SHiP will be sensitive to $f_a$ values that are over an order of magnitude above the existing constraints.

Figures

Figures reproduced from arXiv: 2507.15271 by the authors.

Figure 1
Figure 1. FIG. 1. Tau decays involving LFV (top left) and LFC (bot [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. FIG. 2. Differential branching ratios for various tau de [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 3
Figure 3. FIG. 3. The ALP decay branching ratios in the LFV anarchy [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
Figures from the paper (9 more)
Figure 4
Figure 4. Figure 4: FIG. 4. Left: the normalized differential tau production rate at the collision point as function of the tau transverse momentum [PITH_FULL_IMAGE:figures/full_fig_p006_4.png]
Figure 5
Figure 5. Figure 5: FIG. 5. The energy distribution of ALPs produced in LFV (top row) and LFC (bottom row) decays of taus at NuMI (left [PITH_FULL_IMAGE:figures/full_fig_p007_5.png]
Figure 6
Figure 6. Figure 6: FIG. 6. The parameter space of flavor-violating ALPs with flavor anarchical couplings, Eq. ( [PITH_FULL_IMAGE:figures/full_fig_p011_6.png]
Figure 7
Figure 7. Figure 7: FIG. 7. Same as Fig [PITH_FULL_IMAGE:figures/full_fig_p012_7.png]
Figure 8
Figure 8. Figure 8: FIG. 8. Limits and projected event-rate sensitivities in the [PITH_FULL_IMAGE:figures/full_fig_p013_8.png]
Figure 9
Figure 9. Figure 9: FIG. 9. Same as Fig [PITH_FULL_IMAGE:figures/full_fig_p014_9.png]
Figure 10
Figure 10. Figure 10: FIG. 10. The [PITH_FULL_IMAGE:figures/full_fig_p018_10.png]
Figure 11
Figure 11. Figure 11: FIG. 11. The projected event-rate sensitivities of NOvA [PITH_FULL_IMAGE:figures/full_fig_p020_11.png]
Figure 12
Figure 12. Figure 12: FIG. 12. The [PITH_FULL_IMAGE:figures/full_fig_p021_12.png]

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Reference graph

Works this paper leans on

142 extracted references · 12 canonical work pages · cited by 6 Pith papers

  1. [44]

    A facility to Search for Hidden Particles at the CERN SPS: the SHiP physics case,

    S. Alekhin et al., “A facility to Search for Hidden Particles at the CERN SPS: the SHiP physics case,” Rept. Prog. Phys.79 no. 12, (2016) 124201, arXiv:1504.04855 [hep-ph]

    arXiv 2016

  2. [53]

    Feynman x and transverse momentum dependence of D meson production in 250-GeV pi, K and p - nucleon interactions,

    E769 Collaboration, G. A. Alves et al., “Feynman x and transverse momentum dependence of D meson production in 250-GeV pi, K and p - nucleon interactions,” Phys. Rev. Lett.77 (1996) 2392–2395

    1996

  3. [1]

    NuMI: 2 .9 × 10−7 τ ±/pNT

  4. [2]

    SPS: 1 .7 × 10−6 τ ±/pNT

  5. [3]

    supernova gee,µµ,eµ

    LHC: tau production cross section σtot τ = 0.22 mb. Figure 4 displays the kinematic distributions of the pro- duced τ ± leptons. The simulated samples correspond to approximately 2.2 × 106 τ ’s for NuMI, 6.1 × 106 for SPS, and 2 .1 × 106 for the LHC. In Appendix A, we discuss potential uncertainties in these predictions and their im- pact on the experimen...

    2017

  6. [4]

    The τ → πντ a decay We begin with the decay mode τ − → π−ντ a. The amplitude of this process is given by iM = τ,P ντ ,p2 π,p1a,p3 + τ,P ντ ,p2 π,p1 a,p3 = − √ 2iGF Vudfπmτ gτ τ fa(m2τ − ¯m2τ ) ¯uνPR h mτ /p12 − ¯m2 τ i uτ , (C.1) where PR = (1 + γ5)/2, pij = pi + pj, and ¯m2 τ = p2 12 is the invariant mass of the intermediate off-shell τ (in the first dia...

  7. [5]

    A New Light Boson?,

    S. Weinberg, “A New Light Boson?,” Phys. Rev. Lett. 40 (1978) 223–226

    1978

  8. [6]

    The τ → ρντ a decay The calculation of partial decay width for τ − → ρ−ντ a, is analogous to the one for τ − → π−ντ a. The amplitude is given by iM = τ,P ντ ,p2 ρ,p1a,p3 + τ,P ντ ,p2 ρ,p1 a,p3 = − √ 2GF Vudmρmτ fρgτ τ fa(m2τ − ¯m2τ ) ¯uνPR/ϵ∗ h /p12 − mτ i uτ , (C.6) where we again note the contribution from the second diagram. After performing the phase ...

Show all 142 references
  1. [7]

    The τ → ℓνℓντ a decay The calculation of the partial decay width for τ − → ℓ− ¯νℓντ a, is more complicated, since it involves integrat- ing over the four-body phase space. The amplitude is given by iM = τ,P a,p1 l,p2 ντ ,p3 ¯νl,p4 p234 + · · · = − 2 √ 2GF gτ τmτ fa(p2 234 − m2...

  2. [8]

    This process is identical to the chiral anomaly in the limit mℓ → 0, and therefore we need some care on the regularization

    The a → γγ decay Finally, we consider the ALP decay mode a → γγ through the loop of a heavy lepton ℓ. This process is identical to the chiral anomaly in the limit mℓ → 0, and therefore we need some care on the regularization. The amplitude is diagrammatically expressed as iM =...

  3. [9]

    Physics Beyond Colliders at CERN: Beyond the Standard Model Working Group Report,

    J. Beacham et al., “Physics Beyond Colliders at CERN: Beyond the Standard Model Working Group Report,” J. Phys. G47 no. 1, (2020) 010501, arXiv:1901.09966 [hep-ex]

    2020 arXiv

  4. [10]

    US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report,

    M. Battaglieri et al., “US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report,” in U.S. Cosmic Visions: New Ideas in Dark Matter. 7, 2017. arXiv:1707.04591 [hep-ph]

    2017 arXiv

  5. [11]

    The Search for Feebly Interacting Particles,

    G. Lanfranchi, M. Pospelov, and P. Schuster, “The Search for Feebly Interacting Particles,” Ann. Rev. Nucl. Part. Sci.71 (2021) 279–313, arXiv:2011.02157 [hep-ph]

    2021 arXiv

  6. [12]

    CP Conservation in the Presence of Instantons,

    R. D. Peccei and H. R. Quinn, “CP Conservation in the Presence of Instantons,” Phys. Rev. Lett.38 (1977) 1440–1443. 22

    1977

  7. [13]

    Looking forward to lepton-flavor-violating ALPs,

    L. Calibbi, D. Redigolo, R. Ziegler, and J. Zupan, “Looking forward to lepton-flavor-violating ALPs,” JHEP 09 (2021) 173, arXiv:2006.04795 [hep-ph]

    2021 arXiv

  8. [14]

    Problem of Strong P and T Invariance in the Presence of Instantons,

    F. Wilczek, “Problem of Strong P and T Invariance in the Presence of Instantons,” Phys. Rev. Lett.40 (1978) 279–282

    1978

  9. [15]

    Flavor at F ASER: Discovering Light Scalars Beyond Minimal Flavor Violation,

    R. Balkin, N. Burger, J. L. Feng, and Y. Shadmi, “Flavor at F ASER: Discovering Light Scalars Beyond Minimal Flavor Violation,” arXiv:2412.15197 [hep-ph]

    arXiv

  10. [16]

    Light scalar beyond the Higgs mixing limit,

    C. Delaunay, T. Kitahara, Y. Soreq, and J. Zupan, “Light scalar beyond the Higgs mixing limit,” arXiv:2501.16477 [hep-ph]

  11. [17]

    Review of particle physics,

    Particle Data Group Collaboration, S. Navas et al., “Review of particle physics,” Phys. Rev. D110 no. 3, (2024) 030001

    2024

  12. [18]

    Search for Right-Handed Currents in Muon Decay,

    A. Jodidio et al., “Search for Right-Handed Currents in Muon Decay,” Phys. Rev. D34 (1986) 1967. [Erratum: Phys.Rev.D 37, 237 (1988)]

    1986

  13. [19]

    Search for two body muon decay signals,

    TWIST Collaboration, R. Bayes et al., “Search for two body muon decay signals,” Phys. Rev. D91 no. 5, (2015) 052020, arXiv:1409.0638 [hep-ex]

    2015 arXiv

  14. [20]

    Improved search for two body muon decay µ+→e+XH ,

    PIENU Collaboration, A. Aguilar-Arevalo et al., “Improved search for two body muon decay µ+→e+XH ,” Phys. Rev. D101 no. 5, (2020) 052014, arXiv:2002.09170 [hep-ex]

    2020 arXiv

  15. [21]

    Deep Underground Neutrino Experiment (DUNE) Near Detector Conceptual Design Report,

    DUNE Collaboration, V. Hewes et al., “Deep Underground Neutrino Experiment (DUNE) Near Detector Conceptual Design Report,” Instruments 5 no. 4, (2021) 31, arXiv:2103.13910 [physics.ins-det]

    2021

  16. [22]

    New Opportunities for Detecting Axion-Lepton Interactions,

    W. Altmannshofer, J. A. Dror, and S. Gori, “New Opportunities for Detecting Axion-Lepton Interactions,” Phys. Rev. Lett.130 no. 24, (2023) 241801, arXiv:2209.00665 [hep-ph]

    2023 arXiv

  17. [23]

    Best-fit parameters for τ + and τ − production in pp collisions, grouped by transverse momentum (pT ) and Feynman- x (xF ) distributions

    Integrating this expression over m2 23 from 19 Parameter NuMI SPS LHC NuMI SPS LHC τ + τ − Gamma distribution fits in pT g1 2047052.33 2869884.82 29.95 84411.01 9496674.67 22.30 m1 1.684 1.440 0.857 1.896 1.511 0.850 µ1 1.578 1.729 2.682 1.473 1.674 2.839 λ1 0.964 0.875 0.660 ...

  18. [24]

    Leptophilic axionlike particles at forward detectors,

    X.-H. Jiang and C.-T. Lu, “Leptophilic axionlike particles at forward detectors,” Phys. Rev. D111 no. 3, (2025) 035035, arXiv:2412.19195 [hep-ph]

    2025 arXiv

  19. [25]

    J. F. Donoghue, E. Golowich, and B. R. Holstein, Dynamics of the Standard Model: Second edition. Cambridge University Press, 11, 2022

    2022

  20. [26]

    Searching for Axionlike Particles in Flavor-Changing Neutral Current Processes,

    E. Izaguirre, T. Lin, and B. Shuve, “Searching for Axionlike Particles in Flavor-Changing Neutral Current Processes,” Phys. Rev. Lett.118 no. 11, (2017) 111802, arXiv:1611.09355 [hep-ph]

    2017 arXiv

  21. [27]

    New constraints on light vectors coupled to anomalous currents,

    J. A. Dror, R. Lasenby, and M. Pospelov, “New constraints on light vectors coupled to anomalous currents,” Phys. Rev. Lett.119 no. 14, (2017) 141803, arXiv:1705.06726 [hep-ph]

    2017 arXiv

  22. [28]

    Dark forces coupled to nonconserved currents,

    J. A. Dror, R. Lasenby, and M. Pospelov, “Dark forces coupled to nonconserved currents,” Phys. Rev. D96 no. 7, (2017) 075036, arXiv:1707.01503 [hep-ph]

    2017 arXiv

  23. [29]

    BDF/SHiP at the ECN3 high-intensity beam facility,

    SHiP Collaboration, R. Albanese, J. Alt, A. Alexandrov, S. Aoki, et al., “BDF/SHiP at the ECN3 high-intensity beam facility,” tech. rep., CERN, Geneva, 2023. https://cds.cern.ch/record/2878604

    2023

  24. [30]

    New physics searches using ProtoDUNE and the CERN SPS accelerator,

    P. Coloma, J. L´ opez-Pav´ on, L. Molina-Bueno, and S. Urrea, “New physics searches using ProtoDUNE and the CERN SPS accelerator,” JHEP 01 (2024) 134, arXiv:2304.06765 [hep-ph]

    2024 arXiv

  25. [31]

    Search for dark photons with the F ASER detector at the LHC,

    F ASERCollaboration, H. Abreu et al., “Search for dark photons with the F ASER detector at the LHC,” Phys. Lett. B848 (2024) 138378, arXiv:2308.05587 [hep-ex]

    2024 arXiv

  26. [32]

    The Forward Physics Facility at the Large Hadron Collider,

    FPF W orking GroupsCollaboration, L. A. Anchordoqui et al., “The Forward Physics Facility at the Large Hadron Collider,” 3, 2025. arXiv:2503.19010 [hep-ex]

    2025 arXiv

  27. [33]

    Probing the Higgs Portal at the Fermilab Short-Baseline Neutrino Experiments,

    B. Batell, J. Berger, and A. Ismail, “Probing the Higgs Portal at the Fermilab Short-Baseline Neutrino Experiments,” Phys. Rev. D100 no. 11, (2019) 115039, arXiv:1909.11670 [hep-ph]

    2019

  28. [34]

    Search for a Hidden Sector Scalar from Kaon Decay in the Di-Muon Final State at ICARUS,

    ICARUS Collaboration, F. A. Alrahman et al., “Search for a Hidden Sector Scalar from Kaon Decay in the Di-Muon Final State at ICARUS,” arXiv:2411.02727 [hep-ex]

  29. [35]

    The NOvA Technical Design Report,

    NOvA Collaboration, D. S. Ayres et al., “The NOvA Technical Design Report,”

  30. [36]

    Search for a Higgs Portal Scalar Decaying to Electron-Positron Pairs in the MicroBooNE Detector,

    MicroBooNE Collaboration, P. Abratenko et al., “Search for a Higgs Portal Scalar Decaying to Electron-Positron Pairs in the MicroBooNE Detector,” Phys. Rev. Lett.127 no. 15, (2021) 151803, arXiv:2106.00568 [hep-ex]

    2021 arXiv

  31. [37]

    Search for Heavy Neutrino Decays in the BEBC Beam Dump Experiment,

    W A66Collaboration, A. M. Cooper-Sarkar et al., “Search for Heavy Neutrino Decays in the BEBC Beam Dump Experiment,” Phys. Lett. B160 (1985) 207–211

    1985

  32. [38]

    Blast from the past II: Constraints on heavy neutral leptons from the BEBC W A66 beam dump experiment,

    R. Barouki, G. Marocco, and S. Sarkar, “Blast from the past II: Constraints on heavy neutral leptons from the BEBC W A66 beam dump experiment,” SciPost Phys. 13 (2022) 118, arXiv:2208.00416 [hep-ph]

    2022 arXiv

  33. [39]

    Search for Axion Like Particle Production in 400-GeV Proton - Copper Interactions,

    CHARM Collaboration, F. Bergsma et al., “Search for Axion Like Particle Production in 400-GeV Proton - Copper Interactions,” Phys. Lett. B157 (1985) 458–462

    1985

  34. [40]

    A Search for Decays of Heavy Neutrinos in the Mass Range 0.5-GeV to 2.8-GeV,

    CHARM Collaboration, F. Bergsma et al., “A Search for Decays of Heavy Neutrinos in the Mass Range 0.5-GeV to 2.8-GeV,” Phys. Lett. B166 (1986) 473–478

    1986

  35. [41]

    A comprehensive guide to the physics and usage of PYTHIA 8.3,

    C. Bierlich et al., “A comprehensive guide to the physics and usage of PYTHIA 8.3,” SciPost Phys. Codeb. 2022 (2022) 8, arXiv:2203.11601 [hep-ph]

    2022 arXiv

  36. [42]

    Tuning PYTHIA 8.1: the Monash 2013 Tune,

    P. Skands, S. Carrazza, and J. Rojo, “Tuning PYTHIA 8.1: the Monash 2013 Tune,” Eur. Phys. J. C74 no. 8, (2014) 3024, arXiv:1404.5630 [hep-ph]

    2014 arXiv

  37. [43]

    GeV-scale neutrinos: interactions with mesons and DUNE sensitivity,

    P. Coloma, E. Fern´ andez-Mart ´ ınez, M. Gonz´ alez-L´ opez, J. Hern´ andez-Garc ´ ıa, and Z. Pavlovic, “GeV-scale neutrinos: interactions with mesons and DUNE sensitivity,” Eur. Phys. J. C81 no. 1, (2021) 78, arXiv:2007.03701 [hep-ph]

    2021 arXiv

  38. [45]

    Prompt neutrinos and intrinsic charm at SHiP,

    W. Bai and M. H. Reno, “Prompt neutrinos and intrinsic charm at SHiP,” JHEP 02 (2019) 077, arXiv:1807.02746 [hep-ph]

    2019 arXiv

  39. [46]

    Production asymmetry of ντ neutrinos and ντ antineutrinos from a fixed target experiment SHiP,

    R. Maciu la, A. Szczurek, J. Zaremba, and I. Babiarz, “Production asymmetry of ντ neutrinos and ντ antineutrinos from a fixed target experiment SHiP,” JHEP 01 (2020) 116, arXiv:1910.01402 [hep-ph]

    2020 arXiv

  40. [47]

    Neutrino rate predictions for F ASER,

    F ASERCollaboration, R. Mammen Abraham et al., “Neutrino rate predictions for F ASER,” Phys. Rev. D 110 no. 1, (2024) 012009, arXiv:2402.13318 [hep-ex]. 23

    2024 arXiv

  41. [48]

    DsTau: Study of tau neutrino production with 400 GeV protons from the CERN-SPS,

    DsT auCollaboration, S. Aoki et al., “DsTau: Study of tau neutrino production with 400 GeV protons from the CERN-SPS,” JHEP 01 (2020) 033, arXiv:1906.03487 [hep-ex]

    2020 arXiv

  42. [49]

    Reconstruction of 400 GeV/c proton interactions with the SHiP-charm project,

    SHiP Collaboration, C. Ahdida et al., “Reconstruction of 400 GeV/c proton interactions with the SHiP-charm project,” Eur. Phys. J. C84 no. 6, (2024) 562, arXiv:2406.04730 [hep-ex]

    2024 arXiv

  43. [50]

    First Measurement of the Muon Neutrino Interaction Cross Section and Flux as a Function of Energy at the LHC with F ASER,

    F ASERCollaboration, R. Mammen Abraham et al., “First Measurement of the Muon Neutrino Interaction Cross Section and Flux as a Function of Energy at the LHC with F ASER,”arXiv:2412.03186 [hep-ex]

    arXiv

  44. [51]

    Tuning pythia for forward physics experiments,

    M. Fieg, F. Kling, H. Schulz, and T. Sj¨ ostrand, “Tuning pythia for forward physics experiments,” Phys. Rev. D109 no. 1, (2024) 016010, arXiv:2309.08604 [hep-ph]

    2024 arXiv

  45. [52]

    On the impact of heavy meson production spectra on searches for heavy neutral leptons,

    J. L. Schubert, B. D¨ obrich, J. Jerhot, and T. Spadaro, “On the impact of heavy meson production spectra on searches for heavy neutral leptons,” JHEP 02 (2025) 140, arXiv:2407.08673 [hep-ph]

    2025 arXiv

  46. [54]

    F ASER2 Overview

    A. Barr, “F ASER2 Overview.” Presented at the fpf8 workshop, January, 2025. https://indico.cern.ch/event/1473651/ contributions/6284552/attachments/3000335/ 5287123/FASER2-2025-01-22.pdf

    2025

  47. [55]

    First measurement of νe and ¯νe charged current single charged pion production differential cross sections on argon using the MicroBooNE detector,

    MicroBooNE Collaboration, P. Abratenko et al., “First measurement of νe and ¯νe charged current single charged pion production differential cross sections on argon using the MicroBooNE detector,” arXiv:2503.23384 [hep-ex]

    arXiv

  48. [56]

    Discovering long-lived particles at DUNE,

    P. Coloma, J. Mart ´ ın-Albo, and S. Urrea, “Discovering long-lived particles at DUNE,” Phys. Rev. D109 no. 3, (2024) 035013, arXiv:2309.06492 [hep-ph]

    2024 arXiv

  49. [57]

    Search for long-lived heavy neutral leptons and Higgs portal scalars decaying in the MicroBooNE detector,

    MicroBooNE Collaboration, P. Abratenko et al., “Search for long-lived heavy neutral leptons and Higgs portal scalars decaying in the MicroBooNE detector,” Phys. Rev. D106 no. 9, (2022) 092006, arXiv:2207.03840 [hep-ex]

    2022 arXiv

  50. [58]

    Search for Heavy Neutral Leptons in Electron-Positron and Neutral-Pion Final States with the MicroBooNE Detector,

    MicroBooNE Collaboration, P. Abratenko et al., “Search for Heavy Neutral Leptons in Electron-Positron and Neutral-Pion Final States with the MicroBooNE Detector,” Phys. Rev. Lett.132 no. 4, (2024) 041801, arXiv:2310.07660 [hep-ex]

    2024 arXiv

  51. [59]

    New Constraints on Tau-Coupled Heavy Neutral Leptons with Masses mN=280–970 MeV,

    ArgoNeuT Collaboration, R. Acciarri et al., “New Constraints on Tau-Coupled Heavy Neutral Leptons with Masses mN=280–970 MeV,” Phys. Rev. Lett.127 no. 12, (2021) 121801, arXiv:2106.13684 [hep-ex]

    2021 arXiv

  52. [60]

    First Constraints on Heavy QCD Axions with a Liquid Argon Time Projection Chamber Using the ArgoNeuT Experiment,

    ArgoNeuT Collaboration, R. Acciarri et al., “First Constraints on Heavy QCD Axions with a Liquid Argon Time Projection Chamber Using the ArgoNeuT Experiment,” Phys. Rev. Lett.130 no. 22, (2023) 221802, arXiv:2207.08448 [hep-ex]

    2023 arXiv

  53. [61]

    New Limits on Leptophilic Axionlike Particles and Majorons from ArgoNeuT,

    E. Bertuzzo, A. L. Foguel, G. M. Salla, and R. Z. Funchal, “New Limits on Leptophilic Axionlike Particles and Majorons from ArgoNeuT,” Phys. Rev. Lett. 130 no. 17, (2023) 171801, arXiv:2202.12317 [hep-ph]

    2023 arXiv

  54. [62]

    The 2x2 Demonstrator - A demonstrator for the DUNE ND-LAr Near Detector based on the ArgonCube Design,

    DUNE Collaboration, B. Russell, “The 2x2 Demonstrator - A demonstrator for the DUNE ND-LAr Near Detector based on the ArgonCube Design,” PoS T AUP2023(2024) 221

    2024

  55. [63]

    Overview and Status of the 2x2 NDLAr Demonstrator: A Pixel-Based LArTPC Prototype for the DUNE Near Detector,

    DUNE Collaboration, K. Wresilo, “Overview and Status of the 2x2 NDLAr Demonstrator: A Pixel-Based LArTPC Prototype for the DUNE Near Detector,” PoS ICHEP2024 (2025) 176

    2025

  56. [64]

    Search for Leptonic Decays of Dark Photons at NA62,

    NA62 Collaboration, E. Cortina Gil et al., “Search for Leptonic Decays of Dark Photons at NA62,” Phys. Rev. Lett.133 no. 11, (2024) 111802, arXiv:2312.12055 [hep-ex]

    2024 arXiv

  57. [65]

    Search for hadronic decays of feebly-interacting particles at NA62,

    NA62 Collaboration, E. Cortina Gil et al., “Search for hadronic decays of feebly-interacting particles at NA62,” arXiv:2502.04241 [hep-ex]

    arXiv

  58. [66]

    Projection of finalized NA62 beam-dump analyses to the full 2021-2026 statistics,

    NA62 Collaboration, J. Jerhot, “Projection of finalized NA62 beam-dump analyses to the full 2021-2026 statistics,” tech. rep., CERN, Geneva, 2025. https://cds.cern.ch/record/2936260

    2021

  59. [67]

    Limits on neutral light scalar and pseudoscalar particles in a proton beam dump experiment,

    J. Blumlein et al., “Limits on neutral light scalar and pseudoscalar particles in a proton beam dump experiment,” Z. Phys. C51 (1991) 341–350

    1991

  60. [68]

    Limits on the mass of light (pseudo)scalar particles from Bethe-Heitler e+ e- and mu+ mu- pair production in a proton - iron beam dump experiment,

    J. Blumlein et al., “Limits on the mass of light (pseudo)scalar particles from Bethe-Heitler e+ e- and mu+ mu- pair production in a proton - iron beam dump experiment,” Int. J. Mod. Phys. A7 (1992) 3835–3850

    1992

  61. [69]

    Dark Photon and Muon g − 2 Inspired Inelastic Dark Matter Models at the High-Energy Intensity Frontier,

    Y.-D. Tsai, P. deNiverville, and M. X. Liu, “Dark Photon and Muon g − 2 Inspired Inelastic Dark Matter Models at the High-Energy Intensity Frontier,” Phys. Rev. Lett.126 no. 18, (2021) 181801, arXiv:1908.07525 [hep-ph]

    2021 arXiv

  62. [70]

    Searches for long-lived dark photons at proton accelerator experiments,

    Y. Kyselov and M. Ovchynnikov, “Searches for long-lived dark photons at proton accelerator experiments,” Phys. Rev. D111 no. 1, (2025) 015030, arXiv:2409.11096 [hep-ph]

    2025 arXiv

  63. [71]

    Limits for Shortlived Neutral Particles Emitted µ+ or π+ Decay,

    SINDRUM Collaboration, R. Eichler et al., “Limits for Shortlived Neutral Particles Emitted µ+ or π+ Decay,” Phys. Lett. B175 (1986) 101

    1986

  64. [72]

    Electrophobic Scalar Boson and Muonic Puzzles,

    Y.-S. Liu, D. McKeen, and G. A. Miller, “Electrophobic Scalar Boson and Muonic Puzzles,” Phys. Rev. Lett.117 no. 10, (2016) 101801, arXiv:1605.04612 [hep-ph]

    2016 arXiv

  65. [73]

    Electron beam dump constraints on light bosons with lepton flavor violating couplings,

    T. Araki, K. Asai, and T. Shimomura, “Electron beam dump constraints on light bosons with lepton flavor violating couplings,” JHEP 11 (2021) 082, arXiv:2107.07487 [hep-ph]

    2021 arXiv

  66. [74]

    New Fixed-Target Experiments to Search for Dark Gauge Forces,

    J. D. Bjorken, R. Essig, P. Schuster, and N. Toro, “New Fixed-Target Experiments to Search for Dark Gauge Forces,” Phys. Rev. D80 (2009) 075018, arXiv:0906.0580 [hep-ph]

    2009 arXiv

  67. [75]

    Constraints on a very light CP-odd Higgs of the NMSSM and other axion-like particles,

    S. Andreas, O. Lebedev, S. Ramos-Sanchez, and A. Ringwald, “Constraints on a very light CP-odd Higgs of the NMSSM and other axion-like particles,” JHEP 08 (2010) 003, arXiv:1005.3978 [hep-ph]

    2010 arXiv

  68. [76]

    Search for Neutral Metastable Penetrating Particles Produced in the SLAC Beam Dump,

    J. D. Bjorken, S. Ecklund, W. R. Nelson, A. Abashian, C. Church, B. Lu, L. W. Mo, T. A. Nunamaker, and P. Rassmann, “Search for Neutral Metastable Penetrating Particles Produced in the SLAC Beam Dump,” Phys. Rev. D38 (1988) 3375

    1988

  69. [77]

    A Search for Short Lived Axions in an Electron Beam Dump Experiment,

    E. M. Riordan et al., “A Search for Short Lived Axions in an Electron Beam Dump Experiment,” Phys. Rev. Lett. 59 (1987) 755

    1987

  70. [78]

    An Unambiguous Search for a Light Higgs Boson,

    M. Davier and H. Nguyen Ngoc, “An Unambiguous Search for a Light Higgs Boson,” Phys. Lett. B229 (1989) 150–155. 24

    1989

  71. [79]

    Search for a Dark Leptophilic Scalar in e+e− Collisions,

    BaBar Collaboration, J. P. Lees et al., “Search for a Dark Leptophilic Scalar in e+e− Collisions,” Phys. Rev. Lett.125 no. 18, (2020) 181801, arXiv:2005.01885 [hep-ex]

    2020 arXiv

  72. [80]

    Search for a dark leptophilic scalar produced in association with τ +τ - pair in e+e- annihilation at center-of-mass energies near 10.58 GeV,

    Belle Collaboration, D. Biswas et al., “Search for a dark leptophilic scalar produced in association with τ +τ - pair in e+e- annihilation at center-of-mass energies near 10.58 GeV,” Phys. Rev. D109 no. 3, (2024) 032002, arXiv:2207.07476 [hep-ex]

    2024 arXiv

  73. [81]

    Search for pseudoscalar bosons decaying into e+e− pairs in the NA64 experiment at the CERN SPS,

    NA64 Collaboration, Y. M. Andreev et al., “Search for pseudoscalar bosons decaying into e+e− pairs in the NA64 experiment at the CERN SPS,” Phys. Rev. D 104 no. 11, (2021) L111102, arXiv:2104.13342 [hep-ex]

    2021 arXiv

  74. [82]

    Supernova bound on axionlike particles coupled with electrons,

    P. Carenza and G. Lucente, “Supernova bound on axionlike particles coupled with electrons,” Phys. Rev. D 104 no. 10, (2021) 103007, arXiv:2107.12393 [hep-ph]. [Erratum: Phys.Rev.D 110, 049901 (2024)]

    2021 arXiv

  75. [83]

    Supernova production of axion-like particles coupling to electrons, reloaded,

    D. F. G. Fiorillo, T. Pitik, and E. Vitagliano, “Supernova production of axion-like particles coupling to electrons, reloaded,” arXiv:2503.15630 [hep-ph]

    arXiv

  76. [84]

    Low-Energy Supernovae Severely Constrain Radiative Particle Decays,

    A. Caputo, H.-T. Janka, G. Raffelt, and E. Vitagliano, “Low-Energy Supernovae Severely Constrain Radiative Particle Decays,” Phys. Rev. Lett.128 no. 22, (2022) 221103, arXiv:2201.09890 [astro-ph.HE]

    2022 arXiv

  77. [85]

    Leptophilic ALPs in Laboratory Experiments,

    A. Eberhart, M. Fedele, F. Kahlhoefer, E. Ravensburg, and R. Ziegler, “Leptophilic ALPs in Laboratory Experiments,” arXiv:2504.05873 [hep-ph]

  78. [86]

    NA64 Status Report 2020,

    NA64 Collaboration, S. Gninenko, “NA64 Status Report 2020,” tech. rep., CERN, Geneva, 2020. https://cds.cern.ch/record/2719646

    2020

  79. [87]

    Improved limits on a hypothetical X(16.7) boson and a dark photon decaying into e+e− pairs,

    NA64 Collaboration, D. Banerjee et al., “Improved limits on a hypothetical X(16.7) boson and a dark photon decaying into e+e− pairs,” Phys. Rev. D101 no. 7, (2020) 071101, arXiv:1912.11389 [hep-ex]

    2020 arXiv

  80. [88]

    First Results in the Search for Dark Sectors at NA64 with the CERN SPS High Energy Muon Beam,

    NA64 Collaboration, Y. M. Andreev et al., “First Results in the Search for Dark Sectors at NA64 with the CERN SPS High Energy Muon Beam,” Phys. Rev. Lett. 132 no. 21, (2024) 211803, arXiv:2401.01708 [hep-ex]

    2024 arXiv

  81. [89]

    Probing MeV to 90 GeV axion-like particles with LEP and LHC,

    J. Jaeckel and M. Spannowsky, “Probing MeV to 90 GeV axion-like particles with LEP and LHC,” Phys. Lett. B 753 (2016) 482–487, arXiv:1509.00476 [hep-ph]

    2016 arXiv

  82. [90]

    Sensitivities to feebly interacting particles: Public and unified calculations,

    M. Ovchynnikov, J.-L. Tastet, O. Mikulenko, and K. Bondarenko, “Sensitivities to feebly interacting particles: Public and unified calculations,” Phys. Rev. D 108 no. 7, (2023) 075028, arXiv:2305.13383 [hep-ph]

    2023 arXiv

  83. [91]

    New bounds on axion-like particles from MicroBooNE,

    P. Coloma, P. Hern´ andez, and S. Urrea, “New bounds on axion-like particles from MicroBooNE,” JHEP 08 (2022) 025, arXiv:2202.03447 [hep-ph]

    2022 arXiv

  84. [92]

    Sensitivity to kaon decays to ALPs at fixed target experiments,

    J. Berger and G. Putnam, “Sensitivity to kaon decays to ALPs at fixed target experiments,” Phys. Rev. D 110 no. 5, (2024) 055035, arXiv:2405.18480 [hep-ph]

    2024 arXiv

  85. [93]

    A Search for lepton flavor violating decays τ → eα, τ→ µα,

    ARGUS Collaboration, H. Albrecht et al., “A Search for lepton flavor violating decays τ → eα, τ→ µα,” Z. Phys. C 68 (1995) 25–28

    1995

  86. [94]

    Search for lepton-flavor-violating tau decays to ℓα at Belle,

    Belle Collaboration, K. Uno et al., “Search for lepton-flavor-violating tau decays to ℓα at Belle,” arXiv:2503.22195 [hep-ex]

    arXiv

  87. [95]

    Search for Lepton-Flavor-Violating τ Decays to a Lepton and an Invisible Boson at Belle II,

    Belle-II Collaboration, I. Adachi et al., “Search for Lepton-Flavor-Violating τ Decays to a Lepton and an Invisible Boson at Belle II,” Phys. Rev. Lett.130 no. 18, (2023) 181803, arXiv:2212.03634 [hep-ex]

    2023 arXiv

  88. [96]

    Limits on tau Lepton-Flavor Violating Decays in three charged leptons,

    BaBar Collaboration, J. P. Lees et al., “Limits on tau Lepton-Flavor Violating Decays in three charged leptons,” Phys. Rev. D81 (2010) 111101, arXiv:1002.4550 [hep-ex]

    2010 arXiv

  89. [97]

    Search for Lepton Flavor Violating Tau Decays into Three Leptons with 719 Million Produced Tau+Tau- Pairs,

    K. Hayasaka et al., “Search for Lepton Flavor Violating Tau Decays into Three Leptons with 719 Million Produced Tau+Tau- Pairs,” Phys. Lett. B687 (2010) 139–143, arXiv:1001.3221 [hep-ex]

    2010 arXiv

  90. [98]

    Probing lepton flavour violation via neutrinoless τ − →3µ decays with the ATLAS detector,

    A TLASCollaboration, G. Aad et al., “Probing lepton flavour violation via neutrinoless τ − →3µ decays with the ATLAS detector,” Eur. Phys. J. C76 no. 5, (2016) 232, arXiv:1601.03567 [hep-ex]

    2016 arXiv

  91. [99]

    Search for the lepton flavor violating decay τ → 3µ in proton-proton collisions at √s = 13 TeV,

    CMS Collaboration, A. M. Sirunyan et al., “Search for the lepton flavor violating decay τ → 3µ in proton-proton collisions at √s = 13 TeV,” JHEP 01 (2021) 163, arXiv:2007.05658 [hep-ex]

    2021 arXiv

  92. [100]

    Search for the lepton flavour violating decay τ − → µ− µ+ µ−,

    LHCb Collaboration, R. Aaij et al., “Search for the lepton flavour violating decay τ − → µ− µ+ µ−,” JHEP 02 (2015) 121, arXiv:1409.8548 [hep-ex]

    2015 arXiv

  93. [101]

    Search for lepton-flavor-violating τ −→ µ−µ+µ− decays at Belle II,

    Belle-II Collaboration, I. Adachi et al., “Search for lepton-flavor-violating τ −→ µ−µ+µ− decays at Belle II,” JHEP 09 (2024) 062, arXiv:2405.07386 [hep-ex]

    2024 arXiv

  94. [102]

    The Physics of Hadronic Tau Decays,

    M. Davier, A. Hocker, and Z. Zhang, “The Physics of Hadronic Tau Decays,” Rev. Mod. Phys.78 (2006) 1043–1109, arXiv:hep-ph/0507078

    2006 arXiv

  95. [103]

    QED at NNLO with McMule,

    P. Banerjee, T. Engel, A. Signer, and Y. Ulrich, “QED at NNLO with McMule,” SciPost Phys. 9 (2020) 027, arXiv:2007.01654 [hep-ph]

    2020 arXiv

  96. [104]

    Fully differential NLO predictions for the radiative decay of muons and taus,

    G. M. Pruna, A. Signer, and Y. Ulrich, “Fully differential NLO predictions for the radiative decay of muons and taus,” Phys. Lett. B772 (2017) 452–458, arXiv:1705.03782 [hep-ph]

    2017 arXiv

  97. [105]

    Measurement of the low-energy end of the mu-plus decay spectrum,

    S. E. Derenzo, “Measurement of the low-energy end of the mu-plus decay spectrum,” Phys. Rev. 181 (1969) 1854–1866

    1969

  98. [106]

    Search for exotic muon decays,

    R. Bilger, K. Foehl, H. Clement, M. Croni, A. Erhardt, R. Meier, J. Patzold, and G. J. Wagner, “Search for exotic muon decays,” Phys. Lett. B446 (1999) 363–367, arXiv:hep-ph/9811333

    1999 arXiv

  99. [107]

    Flavor probes of axion-like particles,

    M. Bauer, M. Neubert, S. Renner, M. Schnubel, and A. Thamm, “Flavor probes of axion-like particles,” JHEP 09 (2022) 056, arXiv:2110.10698 [hep-ph]

    2022 arXiv

  100. [108]

    New limit on the µ+->e+γ decay with the MEG II experiment,

    MEG II Collaboration, K. Afanaciev et al., “New limit on the µ+->e+γ decay with the MEG II experiment,” arXiv:2504.15711 [hep-ex]

    arXiv

  101. [109]

    Searches for Lepton Flavor Violation in the Decays τ ± → e±γ and τ ± → µ±γ,

    BaBar Collaboration, B. Aubert et al., “Searches for Lepton Flavor Violation in the Decays τ ± → e±γ and τ ± → µ±γ,” Phys. Rev. Lett.104 (2010) 021802, arXiv:0908.2381 [hep-ex]

    2010 arXiv

  102. [110]

    Search for lepton-flavor-violating tau-lepton decays to ℓγ at Belle,

    Belle Collaboration, A. Abdesselam et al., “Search for lepton-flavor-violating tau-lepton decays to ℓγ at Belle,” JHEP 10 (2021) 19, arXiv:2103.12994 [hep-ex]

    2021 arXiv

  103. [111]

    Supernova constraints on lepton flavor violating ALPs,

    Y. Li and Z. Liu, “Supernova constraints on lepton flavor violating ALPs,” arXiv:2501.12075 [hep-ph]

  104. [112]

    W -Boson Exotic Decay into Three Charged Leptons at the LHC,

    Y. Fei, P. Li, Z. Liu, K.-F. Lyu, and M. Pospelov, “W -Boson Exotic Decay into Three Charged Leptons at the LHC,” arXiv:2407.15930 [hep-ph]

    arXiv

  105. [113]

    Constraints on New Physics in Electron g − 2 from a Search for Invisible Decays of a Scalar, Pseudoscalar, 25 Vector, and Axial Vector,

    NA64 Collaboration, Y. M. Andreev et al., “Constraints on New Physics in Electron g − 2 from a Search for Invisible Decays of a Scalar, Pseudoscalar, 25 Vector, and Axial Vector,” Phys. Rev. Lett.126 no. 21, (2021) 211802, arXiv:2102.01885 [hep-ex]

    2021 arXiv

  106. [114]

    Leptonic scalar portal: Origin of muon g − 2 anomaly and dark matter?,

    NA64 Collaboration, S. N. Gninenko and N. V. Krasnikov, “Leptonic scalar portal: Origin of muon g − 2 anomaly and dark matter?,” Phys. Rev. D106 no. 1, (2022) 015003, arXiv:2202.04410 [hep-ph]

    2022 arXiv

  107. [115]

    Sensitivity potential to a light flavor-changing scalar boson with DUNE and NA64 µ,

    B. Radics, L. Molina-Bueno, L. Fields., H. Sieber, and P. Crivelli, “Sensitivity potential to a light flavor-changing scalar boson with DUNE and NA64 µ,” Eur. Phys. J. C83 no. 9, (2023) 775, arXiv:2306.07405 [hep-ex]

    2023 arXiv

  108. [116]

    Lepton-flavor-violating ALPs at the Electron-Ion Collider: a golden opportunity,

    H. Davoudiasl, R. Marcarelli, and E. T. Neil, “Lepton-flavor-violating ALPs at the Electron-Ion Collider: a golden opportunity,” JHEP 02 (2023) 071, arXiv:2112.04513 [hep-ph]

    2023 arXiv

  109. [117]

    Lepton-flavor-violating ALP signals with TeV-scale muon beams,

    B. Batell, H. Davoudiasl, R. Marcarelli, E. T. Neil, and S. Trojanowski, “Lepton-flavor-violating ALP signals with TeV-scale muon beams,” Phys. Rev. D110 no. 7, (2024) 075039, arXiv:2407.15942 [hep-ph]

    2024 arXiv

  110. [118]

    Probing hidden leptonic scalar portals using the NA64 experiment at CERN,

    A. Ponten, H. Sieber, B. B. Oberhauser, P. Crivelli, D. Kirpichnikov, S. N. Gninenko, M. H¨ osgen, L. M. Bueno, M. Mongillo, and A. Zhevlakov, “Probing hidden leptonic scalar portals using the NA64 experiment at CERN,” Eur. Phys. J. C84 no. 10, (2024) 1035, arXiv:2404.15931 [hep-ph]

    2024 arXiv

  111. [119]

    Measurement of the Positive Muon Anomalous Magnetic Moment to 127 ppb,

    Muon g-2 Collaboration, D. P. Aguillard et al., “Measurement of the Positive Muon Anomalous Magnetic Moment to 127 ppb,” arXiv:2506.03069 [hep-ex]

  112. [120]

    The anomalous magnetic moment of the muon in the Standard Model: an update,

    R. Aliberti et al., “The anomalous magnetic moment of the muon in the Standard Model: an update,” arXiv:2505.21476 [hep-ph]

    arXiv

  113. [121]

    Leading hadronic contribution to the muon magnetic moment from lattice QCD,

    S. Borsanyi et al., “Leading hadronic contribution to the muon magnetic moment from lattice QCD,” Nature 593 no. 7857, (2021) 51–55, arXiv:2002.12347 [hep-lat]

    2021 arXiv

  114. [122]

    Hadronic vacuum polarization for the muon g − 2 from lattice QCD: Long-distance and full light-quark connected contribution,

    A. Bazavov et al., “Hadronic vacuum polarization for the muon g − 2 from lattice QCD: Long-distance and full light-quark connected contribution,” arXiv:2412.18491 [hep-lat]

    arXiv

  115. [123]

    The hadronic vacuum polarization contribution to the muon g − 2 at long distances,

    D. Djukanovic, G. von Hippel, S. Kuberski, H. B. Meyer, N. Miller, K. Ottnad, J. Parrino, A. Risch, and H. Wittig, “The hadronic vacuum polarization contribution to the muon g − 2 at long distances,” JHEP 04 (2025) 098, arXiv:2411.07969 [hep-lat]

    2025 arXiv

  116. [124]

    Long-Distance Window of the Hadronic Vacuum Polarization for the Muon g-2,

    RBC, UKQCD Collaboration, T. Blum et al., “Long-Distance Window of the Hadronic Vacuum Polarization for the Muon g-2,” Phys. Rev. Lett.134 no. 20, (2025) 201901, arXiv:2410.20590 [hep-lat]

    2025 arXiv

  117. [125]

    Measurement of the fine-structure constant as a test of the Standard Model,

    R. H. Parker, C. Yu, W. Zhong, B. Estey, and H. M¨ uller, “Measurement of the fine-structure constant as a test of the Standard Model,” Science 360 (2018) 191, arXiv:1812.04130 [physics.atom-ph]

    2018 arXiv

  118. [126]

    Determination of the fine-structure constant with an accuracy of 81 parts per trillion,

    L. Morel, Z. Yao, P. Clad´ e, and S. Guellati-Kh´ elifa, “Determination of the fine-structure constant with an accuracy of 81 parts per trillion,” Nature 588 no. 7836, (2020) 61–65

    2020

  119. [127]

    Collider Probes of Axion-Like Particles,

    M. Bauer, M. Neubert, and A. Thamm, “Collider Probes of Axion-Like Particles,” JHEP 12 (2017) 044, arXiv:1708.00443 [hep-ph]

    2017 arXiv

  120. [128]

    Hunting for ALPs with Lepton Flavor Violation,

    C. Cornella, P. Paradisi, and O. Sumensari, “Hunting for ALPs with Lepton Flavor Violation,” JHEP 01 (2020) 158, arXiv:1911.06279 [hep-ph]

    2020 arXiv

  121. [129]

    Quark Flavor Phenomenology of the QCD Axion,

    J. Martin Camalich, M. Pospelov, P. N. H. Vuong, R. Ziegler, and J. Zupan, “Quark Flavor Phenomenology of the QCD Axion,” Phys. Rev. D102 no. 1, (2020) 015023, arXiv:2002.04623 [hep-ph]

    2020 arXiv

  122. [130]

    The Belle II Physics Book,

    Belle-II Collaboration, W. Altmannshofer et al., “The Belle II Physics Book,” PTEP 2019 no. 12, (2019) 123C01, arXiv:1808.10567 [hep-ex]. [Erratum: PTEP 2020, 029201 (2020)]

    2019

  123. [131]

    STCF conceptual design report (Volume 1): Physics & detector,

    M. Achasov et al., “STCF conceptual design report (Volume 1): Physics & detector,” Front. Phys. (Beijing) 19 no. 1, (2024) 14701, arXiv:2303.15790 [hep-ex]

    2024

  124. [132]

    Y. Ema, P. J. Fox, M. Hostert, T. Menzo, M. Pospelov, A. Ray, and J. Zupan. In preparation (2025)

    2025

  125. [133]

    Heavy flavour hadro-production from fixed-target to collider energies,

    C. Lourenco and H. K. Wohri, “Heavy flavour hadro-production from fixed-target to collider energies,” Phys. Rept. 433 (2006) 127–180, arXiv:hep-ph/0609101

    2006 arXiv

  126. [134]

    Fragmentation fractions of c and b quarks into charmed hadrons at LEP,

    L. Gladilin, “Fragmentation fractions of c and b quarks into charmed hadrons at LEP,” Eur. Phys. J. C75 no. 1, (2015) 19, arXiv:1404.3888 [hep-ex]

    2015 arXiv

  127. [135]

    The pT spectrum in heavy-flavour hadroproduction.,

    M. Cacciari, M. Greco, and P. Nason, “The pT spectrum in heavy-flavour hadroproduction.,” JHEP 05 (1998) 007, arXiv:hep-ph/9803400

    1998 arXiv

  128. [136]

    The p(T) spectrum in heavy flavor photoproduction,

    M. Cacciari, S. Frixione, and P. Nason, “The p(T) spectrum in heavy flavor photoproduction,” JHEP 03 (2001) 006, arXiv:hep-ph/0102134

    2001 arXiv

  129. [137]

    LHAPDF6: parton density access in the LHC precision era,

    A. Buckley, J. Ferrando, S. Lloyd, K. Nordstr¨ om, B. Page, M. R¨ ufenacht, M. Sch¨ onherr, and G. Watt, “LHAPDF6: parton density access in the LHC precision era,” Eur. Phys. J. C75 (2015) 132, arXiv:1412.7420 [hep-ph]

    2015 arXiv

  130. [138]

    The path to proton structure at 1% accuracy,

    NNPDF Collaboration, R. D. Ball et al., “The path to proton structure at 1% accuracy,” Eur. Phys. J. C 82 no. 5, (2022) 428, arXiv:2109.02653 [hep-ph]

    2022 arXiv

  131. [139]

    Far-forward neutrinos at the Large Hadron Collider,

    W. Bai, M. Diwan, M. V. Garzelli, Y. S. Jeong, and M. H. Reno, “Far-forward neutrinos at the Large Hadron Collider,” JHEP 06 (2020) 032, arXiv:2002.03012 [hep-ph]

    2020 arXiv

  132. [140]

    Forward production of prompt neutrinos from charm in the atmosphere and at high energy colliders,

    W. Bai, M. Diwan, M. V. Garzelli, Y. S. Jeong, K. Kumar, and M. H. Reno, “Forward production of prompt neutrinos from charm in the atmosphere and at high energy colliders,” JHEP 10 (2023) 142, arXiv:2212.07865 [hep-ph]

    2023 arXiv

  133. [141]

    Forward neutrinos from charm at the Large Hadron Collider,

    A. Bhattacharya, F. Kling, I. Sarcevic, and A. M. Stasto, “Forward neutrinos from charm at the Large Hadron Collider,” Phys. Rev. D109 no. 1, (2024) 014040, arXiv:2306.01578 [hep-ph]

    2024 arXiv

  134. [142]

    Predictions for neutrinos and new physics from forward heavy hadron production at the LHC,

    L. Buonocore, F. Kling, L. Rottoli, and J. Sominka, “Predictions for neutrinos and new physics from forward heavy hadron production at the LHC,” Eur. Phys. J. C84 no. 4, (2024) 363, arXiv:2309.12793 [hep-ph]

    2024 arXiv

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